Systems and methods for displaying an image or video on a retro-reflective screen

ABSTRACT

A display system comprises a projector combined with a retro reflective screen and a viewer distance from the projector such that the observation angle is less than approximately 2-3 degrees. The brightness of the image on the screen for the proposed display system is increased by a factor of ˜100-500× as compared to traditional display systems with for an equivalent power/intensity light source.

CROSS-REFERENCE

This application is a continuation application of U.S. patentapplication Ser. No. 14/973,494, filed Dec. 17, 2015, which is acontinuation application of U.S. patent application Ser. No. 13/917,587,filed Jun. 13, 2013, which claims priority to U.S. Provisional PatentApplication Ser. No. 61/660,651, filed Jun. 15, 2012, each of which isentirely incorporated herein by reference.

BACKGROUND

Current state-of-the-art display systems generally consist of eitherflat-panel displays or projector-based displays. The flat-panel displaysare generally based on liquid crystal display (LCD) pixels with lightemitting diode (LED) backlighting or plasma-based screens. In some casesit is difficult to attain screen sizes significantly larger than 80inches in the diagonal dimension due to several considerations. Forflat-panel displays, nonlinear increases in cost as the screen sizegrows, as well as high power consumption, may limit screen sizes tobelow 80 inches at typical consumer price points. For projection-baseddisplays, decreasing screen brightness and increasing power consumption,projector size and projector noise may be significant limitations if thescreen size is increased above 80 inches. Additionally, for both type ofdisplays there is currently no optimal solution for glasses free 3-Dimmersive viewing. Current 3-D display systems rely on either active orpassive glasses, or require the viewer to be located in a substantiallyconstrained region of space in line-of-sight of the display.

SUMMARY

Recognized herein is the need for display systems that are improved inrelation to systems currently available. In particular, recognizedherein is the need for a system that permits multiple viewers to viewindividual customized video streams simultaneously on the same screen aswell as a glasses free 3-D immersive viewing capability. This type ofcapability may enable an immersive multiplayer gaming experience thatdoes not currently exist with display systems currently available.

The present disclosure provides display devices, systems and methods.Some embodiments provide displays utilizing a projector and a reflectivescreen.

The present disclosure provides methods and systems for enabling adisplay system with several properties, including, without limitation:a) Significant power reduction compared to conventional display systemsby a factor on the order of approximately 100-500, b) Significant costand weight reduction by a factor on the order of greater than or equalto about 10 compared to conventional display systems, b) The ability tosimultaneously display multiple video or image streams on the same areaof a shared screen without crosstalk, c) Significantly improved speed,precision and accuracy of real-time image alignment, orientation andmagnification, d) Ultrahigh screen resolution capable of achieving anincreased effective pixel count (>10×) in relation to 1080p displays, e)Glasses free immersive three-dimensional (3-D) viewing capabilitywithout constraints on the viewer's position, and f) The ability toeffectively display an image on a flexible screen.

In an aspect of the present disclosure, a display system comprises aprojector combined with a retro reflective screen and a viewer distancefrom the projector such that the observation angle is small, in somecases less than approximately 2 degrees. The observation angle isdefined as the angle between the line from the projector to any givenlocation on the screen and the line from that same location on thescreen to the eye(s) of the viewer. Another aspect of the inventionprovides methods to manufacture and integrate the projector and screencapabilities. Automated algorithms for enabling fast and precise imagealignment, orientation and magnification are also described herein. Thealgorithms in some cases are implemented with the aid of a computersystem.

In another aspect of the present disclosure, a display system comprisesa retro-reflective screen configured to reflect incident light along adirection that is substantially anti-parallel to the direction ofpropagation of the incident light, and a projector for projecting lightcharacterizing an image or video onto the retro-reflective screenwithout the passage of light through a beam splitter.

In another aspect of the present disclosure, a method for projecting animage or video comprises (a) directing projected light from a projectorto a retro-reflective screen in optical communication with theprojector, wherein the projected light characterizes an image or video,and wherein the retro-reflective screen is configured to reflectincident light along a direction that is substantially anti-parallel tothe direction of propagation of the incident light; and (b) presentinglight reflected from the retro-reflective screen to a viewer that isadjacent to the projector, wherein the viewer is at an observation angleless than about 3° at a distance of at least about 2 feet from theretro-reflective screen.

In another aspect of the present disclosure, a method for determining anedge of a retro-reflective screen comprises (a) directing projectedlight from a projector to a retro-reflective screen in opticalcommunication with the projector while moving one or both of theprojector and the retro-reflective screen in relation to one anothersuch that the projected light scans at least a portion of theretro-reflective screen; and (b) measuring, with the aid of a photodetector adjacent to the projector, reflected light from theretro-reflective screen upon directing the projected light of (a) to theretro-reflective screen. A decrease in intensity of the reflected lightby a factor of at least about 2 is indicative of an edge portion of theretro-reflective screen. In some cases, the method comprises (c)determining, with the aid of a computer processor, an edge portion ofthe retro-reflective screen based upon a decrease in intensity of thereflected light by a factor of at least about 2.

In another aspect of the present disclosure, a method for displaying animage or video comprises (a) directing projected light from a projectorto a retro-reflective screen in optical communication with the projectorwhile moving one or both of the projector and the retro-reflectivescreen in relation to one another such that the projected light scans atleast a portion of the retro-reflective screen; (b) measuring, with theaid of a photo detector adjacent to the projector, reflected light fromthe retro-reflective screen upon directing the projected light of (a) tothe retro-reflective screen; and (c) adjusting the intensity of theprojected light in response to the intensity of the reflected lightmeasured in (b).

In another aspect of the present disclosure, a display system comprisesa retro-reflective screen in optical communication with a projector,wherein the display system does not have a beam splitter.

In another aspect of the present disclosure, a method for projecting animage or video comprises directing projected light from a projector to aretro-reflective screen in optical communication with the projector,wherein upon the directing, the projected light is reflected at anobservation angle less than about 3° at a distance of at least about 2feet from the retro-reflective screen.

In another aspect of the present disclosure, a method for determining aviewing direction and/or orientation of a user (e.g., viewer) inrelation to a viewing screen comprises (a) directing infrared light froman infrared light source to the viewing screen having a retro-reflectiveportion and one or more infrared light-blocking portions; (b) measuring,with the aid of a photo detector adjacent to the infrared light source,reflected infrared light from the viewing screen upon directing theinfrared light to the retro-reflective screen in (a); and (c)correlating, with the aid of a computer processor, (i) a factor of atleast about 2 decrease in intensity of the reflected infrared light withthe transition of a viewing direction and/or orientation of the userfrom the retro-reflective portion to at least a subset of the one ormore infrared blocking portions, and (ii) a factor of at least about 2increase in intensity of the reflected infrared light with thetransition of a viewing direction and/or orientation of the user fromthe one or more infrared light-blocking portions to the retro-reflectiveportion.

In another aspect of the present disclosure, a method for providingthree-dimensional viewing comprises projecting light from a firstprojector and second projector onto a retro-reflective screen, the firstprojector adapted to rest adjacent to a left eye of a user (e.g.,viewer) and the second projector adapted to rest adjacent to a right eyeof the user, wherein light from each of the first projector and secondprojector is at least partially reflected from the retro-reflectivescreen. Reflected light, upon projection from the first projector, mayhave a higher intensity when viewed with the left eye of the user thanthe right eye of the user. Reflected light, upon projection from thesecond projector, may have a higher intensity when viewed with the righteye of the user than the left eye of the user.

Additional aspects and advantages of the present disclosure will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein only exemplary embodiments of the presentdisclosure are shown and described, simply by way of illustration of thebest mode contemplated for carrying out the present disclosure. As willbe realized, the present disclosure is capable of other and differentembodiments, ended several details are capable of modifications invarious obvious respects, all without departing from the disclosure.Accordingly the drawings and description are to be regarded asillustrator for nature, and not as restrictive.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity. Abetter understanding of the features and advantages of the presentinvention will be obtained by reference to the following detaileddescription that sets forth illustrative embodiments, in which theprinciples of the invention are utilized, and the accompanying drawingsof which:

FIG. 1 shows a side view of a projector and retro-reflective screen, inaccordance with an embodiment of the invention;

FIG. 2 shows a front view of a representative retro-reflective screen,in accordance with an embodiment of the invention;

FIG. 3 shows a top view of a schematic showing the capability to havemultiple users/eyes viewing independent image or video sources, inaccordance with an embodiment of the invention;

FIG. 4 a top view of schematic showing the ability to display 3-D videosand images, in accordance with an embodiment of the invention;

FIG. 5 is a perspective view of a schematic showing the ability todynamically detect the edges and size of the retro reflective screen, inaccordance with an embodiment of the invention;

FIG. 6A is a front view of a schematic showing an alternativemethodology to enable real-time determination of the viewer's positionand orientation relative to the retro-reflective screen, in accordancewith an embodiment of the invention;

FIG. 6B is a front view of a schematic showing the use of theaforementioned techniques to enable real-time alignment of left andright projector sources in order to obtain an accurate 3-D visualeffect, in accordance with an embodiment of the invention;

FIG. 7 is a front view of a schematic showing the ability to dynamicallyadjust the project image to match a desired preset size, in accordancewith an embodiment of the invention;

FIG. 8A shows a perspective and a top view of a head mountable projectorwherein there are two projectors one on the left and one on the right,each in close proximity to the left and right eyes respectively, inaccordance with an embodiment of the invention;

FIG. 8B shows a perspective and a top view of a head mountable projectorwherein there is only one projector centered between the two eyes, inaccordance with an embodiment of the invention;

FIG. 9 schematically illustrates a method that enables virtual objectsto be manipulated by one user and observed by multiple users, inaccordance with an embodiment of the invention;

FIG. 10A shows a front view of a schematic showing a conventionaldisplay with a uniform resolution across the surface of the display, inaccordance with an embodiment of the invention;

FIG. 10B schematically illustrates a display having a variable pixeldensity or resolution density across the surface of the display, inaccordance with an embodiment of the invention;

FIG. 11 shows a front view of schematic showing a conventional displaywith a default resolution across the surface of the display incomparison to a reduced size, higher pixel per inch resolution displayof the invention;

FIG. 12 shows the top view of a schematic showing that a display systemof the invention is not significantly impacted by non-uniformities inthe screen flatness;

FIG. 13 shows the top view of a schematic showing an additionaladvantage of a display system of the invention to be able to readilydetect local non-uniformities and locally modulate the projectedintensity to compensate;

FIG. 14 shows the top view of a schematic showing the ability of the adisplay system of the invention to locally modulate intensity in orderto compensate for a wide range of incident angles;

FIG. 15 shows a perspective view of a schematic showing how left andright projectors in a head mountable projector may be combined in orderto form one much larger image or video, in accordance with an embodimentof the invention;

FIG. 16 shows the front view of the schematic showing the ability of adisplay of the invention to effectively have a system-level screenresolution significantly higher than that of a conventional displaysystem;

FIG. 17 schematically illustrates a large area display system, inaccordance with an embodiment of the invention; and

FIG. 18 schematically illustrates a computer system programmed orotherwise configured to facilitate methods of the present disclosure.

DETAILED DESCRIPTION

While preferable embodiments of the invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein can be employed in practicing the invention.

The term “retroreflective” (also “retro-reflective” or “retroreflective” herein), as used herein, generally refers to a device orsurface that reflects light back to or towards its source with a minimumscattering of light. In a retroreflective screen, an electromagneticwave is reflected back along a vector that is parallel to but oppositein direction from the source of the wave. A retroreflective screencomprises a retroreflective surface.

The term “projector,” as used herein, generally refers to a system ordevice that is configured to project (or direct) light. The projectedlight can project an image and/or video.

The term “observation angle,” as used herein, generally refers to anangle between a first line directed from a projector to a given locationon a screen and a second line from that same location on the screen toone or more eyes of a user (e.g., viewer).

The present disclosure provides a display system comprising a projectorcombined with a retro reflective screen at a viewer distance from theprojector such that the observation angle (defined by the line from theprojector to a given location on the screen and the line from that samelocation on the screen to the eye or eyes of the viewer) is less thanapproximately 1-3 degrees. In an example, at an observation angle ofabout 1 degree, the intensity is about three times lower versus theintensity at about 0.5 degrees, and at an observation angle of about 2degrees the intensity decreases by another factor of about three versusone degree. The brightness of the image on the screen of the displaysystem can be increased by a factor of about 100 to 500 as compared totraditional display systems with an equivalent power or intensity oflight source.

Projector-Based Display Systems

An aspect of the present disclosure provides a display system comprisinga retro-reflective screen configured to reflect incident light along adirection that is substantially anti-parallel to the direction ofpropagation of the incident light, and a projector for projecting lightcharacterizing an image or video onto the retro-reflective screenwithout the passage of light through a beam splitter. Theretro-reflective screen may reflect incident light from the projector toa viewer without the passage of light through either a beam splitter orany diffuser layers. In some cases, the retro-reflective screen reflectsincident light from the projector to a viewer at an observation anglethat is less than or equal to about 20°, 15°, 10°, 9°, 8°, 7°, 6°, 5°,4°, 3°, 2°, 1.5°, 1°, 0.5°, 0.4°, 0.3°, 0.2°, or 0.1°. In some cases,the observation angle is between about 0.1° and 10°, or 0.2° and 3°. Insome embodiments, the display system can operate without the need of abeam splitter, thereby advantageously providing for reduced complexityand/or cost as well as avoiding a roughly 4× or greater reduction inintensity compared to a system using a beam splitter.

The observation angle can be a function of the distance of the user fromthe retro-reflective screen. In some embodiments, the observation angleis less than about 5°, 4°, 3°, 2°, 1.5°, 1°, 0.5°, 0.4°, 0.3°, 0.2°, or0.1° when the user is at a distance of at least about 1 foot, 2 feet, 3feet, 4 feet, 5 feet, 6 feet, 7 feet, 8 feet, 9 feet, or 10 feet fromthe retro-reflective screen. In an example, the observation angle can beless than about 3° when the user is at a distance of at least about 4feet from the retro-reflective screen. In some cases, the intensity ofreflected light from the retro-reflected screen is a maximum atobservation angle of about 0°, and decreases with increasing observationangle.

Reference will now be made to the figures, wherein like numerals referto like parts throughout. It will be appreciated that the figures andfeatures therein are not necessarily drawn to scale. The direction of aray of light is illustrated by an arrow directed from a light source orreflective surface.

FIG. 1 shows a schematic side view of a system having a projector 101and a retro-reflective screen 102, in accordance with an embodiment ofthe invention. The retro-reflective properties of the screen 102 cause amajority of the light incident upon the screen 102 to be reflected backtowards the projector 101 in a tight directional cone of lightregardless of the incident angle. This is in contrast to someconventional screens which scatter incident light in a relativelyisotropic manner. In such a conventional screen set up only a very smallfraction of the light incident on the screen 102 actually impinges uponthe viewer's eyes 103. Because of the retro-reflective effect with theproposed system, if the viewer's eye 103 is in close proximity to theprojector such that the angle 104 defined by the path 105 from theprojector to the reflective screen and returning 106 to the viewer's eyeis small, then the brightness of the image may be increased by as muchas 100-500 times over a conventional projector and reflective screen setup. The system of FIG. 1 in some cases does not have a beam splitter.

FIG. 2 shows a front view of a retro-reflective screen 201, inaccordance with an embodiment of the invention. The retro-reflectivescreen is comprised of an array of truncated corner cube reflectors 202.The corner cube reflectors 202 may also be comprised of alternativegeometries. Examples of corner cube reflectors are provided in U.S. Pat.No. 5,763,049 to Frey et al. and U.S. Pat. No. 7,261,424 to Smith, whichpatents are entirely incorporated herein by reference. In someembodiments, the size of each of the corner cube reflectors 202 issmaller than the anticipated or predicted pixel size of the projectedimage, with the pixel size determined by the combination of theprojector display system and the distance of the projector from theretro-reflective screen.

FIG. 3 is a top view of a system describing the capability to havemultiple users/eyes 301, 302 and 303 viewing independent image or videosources, in accordance with an embodiment of the invention. Aretro-reflective screen 304 can be configured to have a highlydirectional nature, which may have the result that only eyes in closeproximity to a given projector 305, 306 and 307 will be able to see theimage or video being projected from that projector onto theretro-reflective screen 304. This may enable multiple users to each viewan independent and different video or image within overlapping areas ofa single screen.

FIG. 4 is a top view of schematic showing a system that displaysthree-dimensional (“3-D” or “3D”) videos or images, in accordance withan embodiment of the invention. The system includes dual projectors 401and 402 mounted on or adjacent to the head of a user 403 (eyes shown).The projectors 401 and 402 can be mounted on a housing that is adaptedto secure to the head of a user, or secured to a user's shoulders orother mounting structure that secures to the user's body, such as theuser's back. In some cases, if the distance of the viewer from theretro-reflective screen 404 and the proximity of the viewer's eyes 403to the projector meet certain criteria, independent video streams may beviewed by the left and right eyes of the viewer without the requirementof either active or passive glasses. In some embodiments, 3D viewing isimplemented by having an observation angle from the left eye 403 a tothe left projector 401 being smaller than the observation angle from theright eye 403 b to the left projector 401 by a ratio of about 2 orgreater. Alternatively, 3D viewing is implemented by having anobservation angle from the right eye 403 b to the right projector 402being smaller than the observation angle from the left eye 403 a to theright projector 402 by a ratio of about 2 or greater. For example, ifthe observation angle for the left eye 403 a to the left projector 401is 1 degree, and the observation angle from the right eye 403 b to theleft projector 401 is 4 degrees, then there may be a significantlyreduced intensity for the image projected by the left projector 401 asviewed by the right eye 403 b. In effect, the right eye 403 b mayreceive a small amount of intensity of light from the left projector401, and the left eye 403 a may receive a small amount of intensity oflight from the right projector 402. In this manner, each eye 403 a and403 b will effectively be viewing only the image or video from theprojector adjacent to that eye 401 and 402, respectively. For arepresentative head mounted set up, a 3-D effect can be attained as longas the distance of the viewer from the retro-reflective screen 404 is inthe range of approximately 1 to 30 feet, or 5 to 15 feet. This roughlycoincides with typical viewing distances for a home theater setup or ahome gaming system. The ability to achieve a 3-D video effect withoutthe use of glasses or any other active or inactive film or optics (e.g.,lenses) between the viewers eyes 403 and the screen and also withoutrequiring the viewer 403 to be in a fixed position and orientation withrespect to the screen 404 is unique to this display system andmethodology.

In some examples, for 3D viewing, the left projector 401 is slightly tothe outside of the left eye 403 a and the right projector 402 isslightly to the outside of the right eye 403 b. In some examples, if themedian eye separation is 61 millimeters (mm), then the left projector401 and the right projector 402 can be greater than 61 mm apart. In anexample, the left projector 401 and the right projector 402 are fromabout 75 mm to 90 mm apart.

Systems for Determining Viewer and/or Screen Orientation

Another aspect of the present disclosure provides a method fordetermining an edge of a retro-reflective screen. Light that isprojected from a projector (or “projected light”) is directed to aretro-reflective screen in optical communication with the projectorwhile moving one or both of the projector and the retro-reflectivescreen in relation to one another such that the projected light scans atleast a portion of the retro-reflective screen. With the aid of a photodetector adjacent to the projector, light that is reflected from theretro-reflective screen (or “reflected light”) is measured. A decreasein intensity of the reflected light by a factor of at least about 2 maybe indicative of an edge portion of the retro-reflective screen.

FIG. 5 is a perspective view of a system that dynamically determines theedges and size of a retro reflective screen, in accordance with anembodiment of the invention. In this example, a scanning laser-basedprojector 501 is combined with a retro-reflective screen 502 such thatlow-cost, real-time auto adjustment and alignment of the image can beachieved using a single pixel photo detector 503 rather than a moreexpensive full resolution image capture camera. The figure schematicallyshows that a substantially lower intensity may return to the photodetector 503 when the laser scanning beam 504 is incident upon an areathat is not part of the retro reflective screen, as the retro-reflectivescreen can enable an increase in intensity (in relation to areas that donot have retro-reflective properties) by a factor greater than or equalto about 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, or 200 for areas withretro-reflective properties. Areas that do not have retro-reflectiveproperties can exhibit a decrease in intensity (in relation to areaswith retro-reflective properties) by a factor greater than or equal toabout 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, or 200. The photo detector503 can be a visible light detector, or alternatively can be infrareddetector in combination with an infrared light emitter within theprojector.

FIG. 6A is a front view of a schematic showing an alternativemethodology to enable real-time determination of the viewer's positionand orientation relative to the retro-reflective screen 601, inaccordance with an embodiment of the invention. In this figure thedashed lines 602 represent infrared blocking markings which may betransparent to visible light. The lines 602 are drawn dashed forillustrative clarity; in some cases, the lines 602 may be solid (orcontinuous) lines. Combining these markings with an infrared lightemitter and detector, the viewer's position and orientation relative tothe retro-reflective screen 601 can be readily determined without theneed for a sophisticated video camera or extensive image processing. Inthis example, a non-scanner projector system uses a small percentage ofa frame's duty cycle to project an infrared outline around the perimeterof the display area (outlined in solid black). With the use of a photodetector, each intersection of the display perimeter with one of theinfrared light blocking markings can exhibit itself as a drop inintensity detected by the photo detector. The number and relativeposition of each of these drops in intensity along each of the sides ofthe display perimeter can be used to calculate (in some cases with theaid of a processor) the viewer's position, orientation and tilt (e.g.,head tilt or body tilt) relative to the retro reflective screen 601. Incontrast, conventional systems may require the use of expensive fullresolution image capture camera and complex image process algorithms toattain this information. The determination of these parameters mayprovide a fully immersive 3D display experience wherein the image thatthe viewer sees changes as the viewer moves or rotates. The specificgeometry of the markings are not required to be the rectangular grid, asshown. The marking may have various shapes or geometries, such ascircular, triangular, square, rectangular, pentagonal, hexagonal,heptagonal, octagonal, nonagonal, or partial shapes or combinationsthereof. In some embodiments, the combination of a projector with eitherscanning and/or pixel level control, combined with retro-reflectivenature of the screen 601, enables precise and simple position andorientation determination. Additionally, barcode or other type ofinformation (e.g., numeric identifier, geometric identifier) 603 may beincorporated into different blocking markings to assist in ensuring thataccurate position and orientation parameters are determined.

FIG. 6B is a front view of a schematic showing the use of theaforementioned techniques to enable real-time alignment of left andright projector sources in order to obtain a 3-D visual effect, inaccordance with an embodiment of the invention. In this image, both theleft and right image sources are aligned such that the left and rightimages of a cloud 604 which is far from the user are overlaid on top ofeach other, while a tree 605 which is closer to the user has an offsetbetween the left and right image sources, as schematically indicated bytwo offset images of the tree 605 in the figure. The alignment of theimages can be accomplished by digitally shifting the projected image orvideo rather than manual physical alignment of the left and rightprojector's. In addition to very precise image alignment, this can alsoallow for a lower cost system due to less restrictive physical alignmentrequirements for the left and right projectors.

FIG. 7 is a front view of a schematic showing the ability to dynamicallyadjust a projected image to match a desired preset size, in accordancewith an embodiment of the invention. In this figure the dashed linesrepresent infrared blocking markings that are transparent to visiblelight. With these markings, combined with an infrared light emitter anddetector, the projected image can be automatically adjusted to thedesired preset size.

Mountable Projectors

Another aspect of the present disclosure provides mountable projectors,which may be used in conjunction with retro-reflective screens to enableviewers to view images or videos. Mountable projectors may be mountableon a head or generally a body of a user, or a structure that may be inproximity to the user.

FIG. 8A shows a perspective (top image) and a top view (bottom image) ofa head mountable projector system wherein there are two projectors, oneon the left 801 and one on the right 802 with respect to eyes of theuser. The left projector 801 is next to a left eye 803 of the user, andthe right projector 802 is next to a right eye 804 of the user. Thisconfiguration is schematically representative of a setup that may beused to provide glasses-free 3-D viewing. The projectors 801 and 802 canbe mounted on or adjacent to the head of a user. The projectors can bemounted on a housing that is adapted to secure to the head of a user, orsecured to a user's shoulders or other mounting structure that securesto the user's body, such as the user's back. The projectors can beoriented such that an observation angle between about 1° and 10°, or 2°and 3° is achieved. In some cases, the observation angle is less than orequal to about 20°, 15°, 10°, 9°, 8°, 7°, 6°, 5°, 4°, 3°, 2°, 1.5°, 1°,0.5°, 0.4°, 0.3°, 0.2°, or 0.1°. The observation angle can be a functionof the distance of the user from the retro-reflective screen, asdescribed elsewhere herein. FIG. 8B shows a perspective and a top viewof a head mountable projector 805 wherein there is only one projectorcentered between the two eyes 806 and 807 of the user. The systems ofFIGS. 8A and 8B enable an increase in intensity by a factor of at leastabout 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100,or 200. This can advantageously provide for a weight and size reductionin order to have a small and lightweight head mounted projector system,while also retaining adequate projected display intensity. In someembodiments, the use of dual mounted left and right projectors, as inFIG. 8A, may provide a 3-D glasses-free viewing experience that, in somecases, is achieved via independent video streams being directed to eachof the left and right eyes of the user (or viewer).

In some cases, projectors may be secured to a head of a user (orviewer). Alternatively, projectors may be secured to a body of a viewerwith the aid of a support member that secures to the viewer's body. Sucha setup may enable the height of the projector in relation to theviewer's body to be adjusted such that the projector can be aligned withthe viewer's head. In some cases, however, projectors provided hereincan be aligned with the viewer's head but secure to a mount or structureexternal to the viewer, such as the viewer's chair.

FIG. 9 is a perspective view of a system that can enable a virtualreality experience in which virtual objects can be manipulated by afirst user (or entity) and viewed by one or more viewers (e.g.,participants in a game or virtual reality experience), which may includeany user manipulating the virtual object. The system provides thecapability to display multiple independent image or video streams on thesame area of a retro-reflective screen (not shown). The viewers 901 and902 may each have head mountable projectors 903 and 904. In theillustrated example, a left viewer 901 and right viewer 902 are viewinga manipulated virtual object. The viewer on the left 901 may see a sword905 on the retro-reflective screen towards the right portion of the leftviewer's 901 display area, while the viewer on the right 902 may see thesword 905 on the retro-reflective screen towards the middle or leftportion of the right viewer's 902 display area. The projectors 903 and904 in this example may provide light towards the retro-reflectivescreen.

In an example, a projected image can be associated with a physicalobject. For example, in FIG. 9, the displayed sword can have a handlethat is associated with a physical object (e.g., a game controller), butthe remainder of the displayed sword is an image or video projected onthe retro-reflective screen. This can provide for an augmented realityexperience in which physical objects are associated with virtualobjects.

Display Systems

FIG. 10A schematically illustrates a conventional display with a uniformresolution across the surface of the display. The display of FIG. 10A isimplemented with the aid of a non-retro-reflective screen. FIG. 10Bschematically illustrates a display (or screen) having a variable pixeldensity or resolution density across the surface of the display, inaccordance with an embodiment of the invention. The variable pixeldensity of the display can be implemented in software by using the samepixel information from multiple pixels towards the edge of the displayarea. Variable pixel density displays can be most effectivelyimplemented in the case of a scanning laser or light emitting diode(LED) projector or the pixel density of the projector is not fixed butis rather determined by the combination of the reflecting mirror scanspeed and modulation rate of the laser or LED.

The screen of FIG. 10B has three areas with differing pixel densities(i.e., number of pixels per unit area). A central area has a first pixeldensity, a middle area has a second pixel density and an outer area hasa third pixel density. The first pixel density is greater than thesecond pixel density, and the second pixel density is greater than thethird pixel density.

The screen of FIG. 10B may be suited for head (or body) mountableprojectors described elsewhere herein. Since the human eye has highervisual acuity towards the center of the gaze and lower resolution visionin the periphery due to higher concentration of cone cells towards thecenter of the retina, this approach can be used to increase effectivescreen resolution or screen size or combination of the two. In theillustrated example of FIG. 10B, the center of the image has a higherpixel density, while areas towards the edges of the screen have a lowerpixel density and resolution. By having a non-uniform pixel density inthis manner, a higher effective screen resolution can be achieved. Insome embodiments, the display of FIG. 10B may be effectively implementedwith the aid of a head mountable projector, as described elsewhereherein.

FIG. 11 is a front view of schematic showing a conventional display withthe default resolution across the surface of the display. There may becases where the distance between the viewer/projector and the screen islarge, resulting in a default image size that is larger than desired.One of the advantages of a scanning projector system in conjunction witha retro-reflective screen utilizing corner cube elements smaller thanthe pixel size is that the image can be scaled down to a reduced sizewithout appreciably sacrificing resolution or pixel count. The pixeldensity in such a case can be determined by the projector and is notlimited by the size of the cube elements.

FIG. 12 is a top view of a schematic showing an additional advantage ofa display system of the disclosure using a retro-reflective screen 1201.In this setup, because of the retro-reflective nature of the corner cubeelements, non-uniformities 1202 in the screen flatness do not impact thedirectionality of the reflected image from the screen 1201. Thisproperty enables low-cost manufacturing and installation for theretro-reflective screen 1201 by not requiring overly restrictive surfaceuniformity and/or surface protection schemes. In addition, innovativeform factors and shapes can be used for the screen 1201. For example, onthe right side of this figure an intentionally curved screen 1203 isshown. In some embodiments, retro-reflective screens with surfaceirregularities that can cause incident angle changes of up to about 1°,2°, 3°, 4°, 5°, 10°, or 20° may provide display properties that are notappreciably diminished in relation to screens not having any surfaceirregularities.

FIG. 13 schematically illustrates a display system utilizing thecombination of a scanning laser or light emitting diode (LED) projector1301 with a retro-reflective screen 1302, in accordance with anembodiment of the invention. Light from the laser or LED is directed to1303 the retro-reflective screen 1302, which light is reflected 1304 bythe retro-reflective screen 1302. The left side of this figure shows anexample non-uniformity 1305 on the retro-reflective screen 1302, whichmay cause the intensity of the light returned to the viewer (i.e.,reflected light) to be compromised or otherwise changed with respect tothe intensify of light returned to the viewer from a uniform portion ofthe screen 1302. The non-uniformity 1305 can include one or moreslightly defective corner cube elements, surface flatnessirregularities, dirt, or other obstruction(s) that adversely impacts theretro-reflective properties of the screen. In some cases, thenon-uniformity 1305 effects a decrease in intensity of reflected light.With the use of a photo detector, this local reduction in intensity canbe detected. In subsequent frames of the video, the laser or LEDintensity can be increased for the areas/pixels that require a higherintensity, thus aiding in compensating for the non-uniformity. In thismanner the reflected image intensity can be made to be uniform. Theright figure schematically shows a higher intensity beam of light 1303 adirected to the compromised region 1305 (i.e., the region having thescreen non-uniformity), resulting in a reflected intensity that bettermatches the original desired intensity. Similarly, for a highly curvedscreen surface at the edges of the screen, where the angle of theincident light can deviate significantly from the normal incidenceangle, the reflected light intensity can be significantly reduced. Inthese cases, the laser or LED intensity can be similarly increased inthose regions to compensate for the non-uniformity. This real-timeintensity modulation at a local level cannot be easily accomplished withtraditional display systems which do not incorporate both ascanning-based projector and a retro reflective screen.

Another aspect of the present disclosure provides a method fordisplaying an image or video, comprising directing projected light froma projector to a retro-reflective screen in optical communication withthe projector while moving one or both of the projector and theretro-reflective screen in relation to one another such that theprojected light scans at least a portion of the retro-reflective screen.Next, with the aid of a photo detector adjacent to the projector,reflected light from the retro-reflective screen is measured upondirecting the projected light to the retro-reflective screen. Theintensity of the projected light is adjusted in response to the measuredintensity of reflected light. The intensity of the projected light canbe adjusted to compensate, for example, for screen non-uniformities, orthe angle at which the viewer is oriented in relation to the screen(e.g., normal incidence as opposed to non-normal incidence). In somecases, the intensity of the projected light is adjusted upon comparing,with the aid of a processor, the intensity of the reflected lightagainst one or more set-point intensities.

The system of FIG. 13 can aid in dynamically adjusting projector lightintensity to compensate for any retro-reflective screennon-uniformities. For example, a head or body mountable projector mayinclude a photo detector that detects light reflected from theretro-reflective screen along an observation angle that includes theeyes of a viewer. The photo detector can be coupled to (e.g., in wiredor wireless communication with) a computer processor (see below) that(i) measures reflected light intensity and (ii) dynamically adjusts thelight intensity of the projector in response to any measured decrease inthe intensity of reflected light. The computer processor can measurereflected light and dynamically adjust the intensity of projected lightwithin a time period of at most about 5 seconds, 4 seconds, 3 seconds, 2seconds, 1 second, 1 millisecond, or 1 microsecond, or, alternatively,within a time period nearly or substantially matched to the videorefresh rate, such as, for example, 20-60 hertz (Hz).

Systems of the present disclosure can compensate for a deceasedintensity of reflected light in cases in which the decrease is at leastin part due to viewing angle that deviates for direct normal incidence.FIG. 14 schematically illustrates a system for compensating for adecreased intensity of reflected light, in accordance with an embodimentof the invention. In this case, a projector (bottom right) 1401 isoriented at a screen 1402 at an angle that deviates from normalincidence, as measured with respect to a vector that is orientedperpendicularly with respect to a plane parallel to a surface of thescreen 1402. The reflected intensity from the regions of the imagefarthest 1403 from the projector 1401 may have a lower intensity versusthe regions closer 1404 to the projector 1401. This may be due to theincident angle being smaller for regions farther from the projector1401, as shown in the figure. Again, in this case the intensity of thebeam can be increased in those regions requiring a higher incomingintensity of light in order to match the desired reflected intensity.

FIG. 15 schematically illustrates a system comprising a head (or body)mountable projector having left 1501 and right projectors 1502 that maybe combined to provide a large or wide-area viewing experience, inaccordance with an embodiment of the invention. The projectors 1501 and1502 can be situated adjacent or in proximity to the eyes 1503 of auser. The system of FIG. 15 may be configured for use with images andvideos provided by the projectors. Because of the ability to easilydetect the location of specific pixels projected by each projector ontoa retro-reflective screen 1504, alignment between the left and rightimages can be accomplished without requiring potentially expensive highpixel density detectors or the use of complex image processing.

FIG. 16 schematically illustrates a system having a system-level screenresolution significantly higher than conventional display systems, inaccordance with an embodiment of the invention. The system comprises aretro-reflective screen 1601 and a projector (not shown) that is mountedon head or body of a user. If the video source or immersive media suchas a video game has content that spans beyond a typical pixelresolution, such as, for example, a 1920×1080 pixel resolution, thislarger immersive environment can be viewed using display systems of theinvention. Using a head mountable projector, the user is able to view a1920×1080 image that changes as the user turns and faces a differentportion of the retro-reflective screen. In the illustrated example, afirst region 1602 and a second region 1603 become apparent to the useras the user turns the head of the user to face the first region 1602 orsecond region 1603. In this figure, each of the two smaller regions 1602and 1603 of the screen 1601 can represent a 1920×1080 projected image.The size of the overall image in this example may have a resolutiongreater than about 6000×3000 pixels.

FIG. 17 schematically illustrates a display system that enables a wideor large area viewing experience, in accordance with an embodiment ofthe invention. The system of FIG. 17 comprises a retro-reflective screen1701, a first projector 1702 adjacent to a first user 1703, and a secondprojector 1704 adjacent to a second user 1705. The system can be adaptedfor a long throw distance of at least about 10 feet, 20 feet, 30 feet,40 feet, 50 feet, 100 feet, 200 feet, 300 feet, 400 feet, or 500 feet.For example, with a long throw distance of 100 feet and an observationangle of approximately 1°, the optimal viewing angle may be within theproximity of approximately 1-2 feet from the projector. This largerviewing proximity distance from the projector 1702 or 1704 can allow forthe use of a stationary, non-battery operated projector. With anincrease in intensity by a factor of at least about 2, 3, 4, 5, 6, 7, 8,9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or 200, a projector with2000 to 4000 Lumen brightness rating may have the capability to be ableto project a bright image onto a 100 foot diagonal screen. Additionally,several projectors can be placed such that each projector shows adifferent image or video on the screen. For example, the first user 1703can have a different (e.g., unique) viewing experience than the seconduser 1705. The first user 1703 can view an image or view that isdifferent than the second user 1705. For example, the first user 1703views a cloud while the second user 1705 views a tree. The first user1703 and second user 1705 can be provided with sound to go along witheach user's viewing experience, such as by way of headphones or otherlocal speaker system. Such large area display can be effective foradvertising purposes, or other showcase demonstrations, due, at least inpart, to the qualities of the display size and having multipleimages/videos on the same screen area.

Systems and methods of this disclosure provide various advantages, suchas, without limitation: a) power reduction compared to conventionaldisplay systems, such as reduction by a factor of at least about 100compared to conventional display systems; b) cost and weight reductionby a factor of at least about 10 compared to conventional displaysystems; c) the ability to simultaneously display multiple video and/orimage streams on the same area of a screen; d) improved speed, precisionand accuracy of real-time image alignment, orientation andmagnification; e) ultrahigh screen resolution capable of achieving aneffective pixel count that is increased by a factor of at least about 10in relation to 1080p displays; f) glasses-free immersive 3-D viewingcapability without constraints of the viewers position; and g) theability to accommodate flexible screens. Systems and methods of thepresent disclosure can be use with various electronic devices, such asgaming and/or multimedia devices. Examples of electronic devicesinclude, without limitation, portable electronic devices (e.g., Smartphones), video game systems (e.g., Sony® PlayStation 3, Sony®PlayStation 4, Microsoft® Xbox 360, Microsoft® Xbox One, or Nintendo®Wii), and virtual and/or augmented reality systems. Such electronicdevices can be configured for wired or wireless communication withsystems of the present disclosure.

In some embodiments, a display systems utilizes a projector to displayan image and/or video onto a retro-reflective screen, wherein the systemis set up to have small observation angles resulting in a significantincrease in the light intensity reaching the viewers eye(s) and/or photodetector.

Computer Systems

Another aspect of the present disclosure provides a system that isprogrammed or otherwise configured to implement the methods of thedisclosure. The system can include a computer server that is operativelycoupled to a projector and a photo detector. The projector and photodetector can be standalone units, or integrated as a projection anddetection system.

FIG. 18 shows a system 1800 comprising a computer server (“server”) 1801that is programmed to implement methods disclosed herein. The server1801 includes a central processing unit (CPU, also “processor” and“computer processor” herein) 1805, which can be a single core or multicore processor, or a plurality of processors for parallel processing.The server 1801 also includes memory 1810 (e.g., random-access memory,read-only memory, flash memory), electronic storage unit 1815 (e.g.,hard disk), communication interface 1820 (e.g., network adapter) forcommunicating with one or more other systems, and peripheral devices1825, such as cache, other memory, data storage and/or electronicdisplay adapters. The memory 1810, storage unit 1815, interface 1820 andperipheral devices 1825 are in communication with the CPU 1805 through acommunication bus (solid lines), such as a motherboard. The storage unit1815 can be a data storage unit (or data repository) for storing data.The server 1801 can be operatively coupled to a computer network(“network”) with the aid of the communication interface 1820. Thenetwork can be the Internet, an internet and/or extranet, or an intranetand/or extranet that is in communication with the Internet. The networkin some cases is a telecommunication and/or data network. The networkcan include one or more computer servers, which can enable distributedcomputing, such as cloud computing. The network, in some cases with theaid of the server 1801, can implement a peer-to-peer network, which mayenable devices coupled to the server 1801 to behave as a client or aserver.

The storage unit 1815 can store files or data. The server 1801 caninclude one or more additional data storage units that are external tothe server 1801, such as located on a remote server that is incommunication with the server 1801 through an intranet or the Internet.

In some situations, the system 1800 includes a single server 1801. Inother situations, the system 1800 includes multiple servers incommunication with one another through an intranet and/or the Internet.

The server 1801 can be adapted to store user information and data of orrelated to a projection environment, such as, for example, displayangles and intensity settings. The server 1801 can be programmed todisplay an image or video through a projector coupled to the server1801.

Methods as described herein can be implemented by way of machine (orcomputer processor) executable code (or software) stored on anelectronic storage location of the server 1801, such as, for example, onthe memory 1810 or electronic storage unit 1815. During use, the codecan be executed by the processor 1805. In some cases, the code can beretrieved from the storage unit 1815 and stored on the memory 1810 forready access by the processor 1805. In some situations, the electronicstorage unit 1815 can be precluded, and machine-executable instructionsare stored on memory 1810.

The code can be pre-compiled and configured for use with a machine havea processer adapted to execute the code, or can be compiled duringruntime. The code can be supplied in a programming language that can beselected to enable the code to execute in a pre-compiled or as-compiledfashion.

The server 1801 is coupled to (e.g., in communication with) a projector1830 and a photo detector 1835. In an example, the projector 1830 canproject an image or video onto a retro-reflective screen. In anotherexample, the project 1830 can project ultraviolet or infrared light ontothe retro-reflective screen. The photo detector 1835 can detect (ormeasure) reflected light from the retro-reflective screen.

The projector 1830 can include one or more optics for directing and/orfocusing an image or video onto the retro-reflective screen. The photodetector can be a device that is configured to generate an electricalcurrent upon exposure to light, such as, for example, a charge-coupleddevice (CCD).

Aspects of the systems and methods provided herein, such as the server1801, can be embodied in programming. Various aspects of the technologymay be thought of as “products” or “articles of manufacture” typicallyin the form of machine (or processor) executable code and/or associateddata that is carried on or embodied in a type of machine readablemedium. Machine-executable code can be stored on an electronic storageunit, such memory (e.g., read-only memory, random-access memory, flashmemory) or a hard disk. “Storage” type media can include any or all ofthe tangible memory of the computers, processors or the like, orassociated modules thereof, such as various semiconductor memories, tapedrives, disk drives and the like, which may provide non-transitorystorage at any time for the software programming. All or portions of thesoftware may at times be communicated through the Internet or variousother telecommunication networks. Such communications, for example, mayenable loading of the software from one computer or processor intoanother, for example, from a management server or host computer into thecomputer platform of an application server. Thus, another type of mediathat may bear the software elements includes optical, electrical andelectromagnetic waves, such as used across physical interfaces betweenlocal devices, through wired and optical landline networks and overvarious air-links. The physical elements that carry such waves, such aswired or wireless links, optical links or the like, also may beconsidered as media bearing the software. As used herein, unlessrestricted to non-transitory, tangible “storage” media, terms such ascomputer or machine “readable medium” refer to any medium thatparticipates in providing instructions to a processor for execution.

Hence, a machine readable medium, such as computer-executable code, maytake many forms, including but not limited to, a tangible storagemedium, a carrier wave medium or physical transmission medium.Non-volatile storage media include, for example, optical or magneticdisks, such as any of the storage devices in any computer(s) or thelike, such as may be used to implement the databases, etc. shown in thedrawings. Volatile storage media include dynamic memory, such as mainmemory of such a computer platform. Tangible transmission media includecoaxial cables; copper wire and fiber optics, including the wires thatcomprise a bus within a computer system. Carrier-wave transmission mediamay take the form of electric or electromagnetic signals, or acoustic orlight waves such as those generated during radio frequency (RF) andinfrared (IR) data communications. Common forms of computer-readablemedia therefore include for example: a floppy disk, a flexible disk,hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD orDVD-ROM, any other optical medium, punch cards paper tape, any otherphysical storage medium with patterns of holes, a RAM, a ROM, a PROM andEPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wavetransporting data or instructions, cables or links transporting such acarrier wave, or any other medium from which a computer may readprogramming code and/or data. Many of these forms of computer readablemedia may be involved in carrying one or more sequences of one or moreinstructions to a processor for execution.

Methods of the disclosure can be facilitated with the aid ofapplications (apps) that can be installed on electronic devices of auser, such as a portable electronic device (e.g., Smart phone, laptopcomputer). Examples of portable electronic devices include, withoutlimitation, Smart phones (e.g., Apple® iPhone®, Apple® iPad®, Samsung®Galaxy Tab®). An app can include a GUI on a display of the electronicdevice of the user. The app can be programmed or otherwise configured toperform various functions of the system.

It should be understood from the foregoing that, while particularimplementations have been illustrated and described, variousmodifications can be made thereto and are contemplated herein. It isalso not intended that the invention be limited by the specific examplesprovided within the specification. While the invention has beendescribed with reference to the aforementioned specification, thedescriptions and illustrations of the preferable embodiments herein arenot meant to be construed in a limiting sense. Furthermore, it shall beunderstood that all aspects of the invention are not limited to thespecific depictions, configurations or relative proportions set forthherein which depend upon a variety of conditions and variables. Variousmodifications in form and detail of the embodiments of the inventionwill be apparent to a person skilled in the art. It is thereforecontemplated that the invention shall also cover any such modifications,variations and equivalents. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

1-33. (canceled)
 34. A display system, comprising: a retroreflectivescreen configured to reflect incident light to a viewer that is at anobservation angle less than about 3° at a distance of at least about 2feet from said retroreflective screen; a projector for projecting lightcharacterizing an image or video directly onto said retroreflectivescreen; and a computer processor in communication with said projector,wherein said computer processor is programmed to (i) measure anintensity of light reflected from said retroreflective screen, and (ii)dynamically adjust said light from said projector in response to saidintensity measured in (i).
 35. The display system of claim 34, whereinsaid computer processor is programmed to dynamically adjust said lightfrom said projector in response to any measured change in said intensityof light reflected from said retro-reflective screen.
 36. The displaysystem of claim 34, wherein said computer processor is programmed todynamically adjust said light from said projector such that said imageor video matches a desired preset size
 37. The display system of claim34, wherein said computer processor is programmed to dynamically adjustsaid light from said projector in response to a change in said intensityof light reflected from said retro-reflective screen.
 38. The displaysystem of claim 4, wherein said computer processor is programmed todynamically adjust said light from said projector in response to adecrease in said intensity of light reflected from said retro-reflectivescreen.
 39. The display system of claim 34, wherein said computerprocessor is programmed to dynamically adjust said light from saidprojector to compensate for non-uniformities of said retroreflectivescreen.
 40. The display system of claim 34, wherein said computerprocessor is programmed to dynamically adjust said light from saidprojector to compensate for an angle at which said viewer is oriented inrelation to said retroreflective screen.
 41. The display system of claim34, wherein said computer processor is programmed to dynamically adjustsaid light from said projector upon comparing said intensity against oneor more set-point intensities.
 42. The display system of claim 34,wherein said computer processor is programmed to measure said intensityof light with the aid of a photodetector.
 43. A method for projecting animage or video, comprising: a. directing light characterizing an imageor video from a projector directly onto a retroreflective screen inoptical communication with said projector; b. presenting light reflectedfrom said retroreflective screen to a viewer that is at an observationangle less than about 3° at a distance of at least about 2 feet fromsaid retroreflective screen; c. measuring an intensity of lightreflected from said retroreflective screen; and d. dynamically adjustsaid light from said projector in response to said intensity measured in(c).
 44. The method of claim 43, further comprising dynamicallyadjusting said light from said projector in response to any measuredchange in said intensity of light reflected from said retro-reflectivescreen.
 45. The method of claim 43, further comprising dynamicallyadjusting said light from said projector such that said image or videomatches a desired preset size
 46. The method of claim 43, furthercomprising dynamically adjusting said light from said projector inresponse to a measured change in said intensity of light reflected fromsaid retro-reflective screen.
 47. The method of claim 46, furthercomprising dynamically adjusting said light from said projector inresponse to a decrease in said intensity of light reflected from saidretro-reflective screen.
 48. The method of claim 43, further comprisingdynamically adjusting said light from said projector to compensate fornon-uniformities of said retroreflective screen.
 49. The method of claim43, further comprising dynamically adjusting said light from saidprojector to compensate for an angle at which said viewer is oriented inrelation to said retroreflective screen.
 50. The method of claim 43,further comprising dynamically adjusting said light from said projectorupon comparing said intensity against one or more set-point intensities.51. The method of claim 43, wherein said intensity of light is measuredwith the aid of a photodetector.